[PATCH 15/21] drm/xe/eudebug: implement userptr_vma access

[Mika Kuoppala]

From: Andrzej Hajda <andrzej.hajda at intel.com>

Debugger needs to read/write program's vmas including userptr_vma.
Since hmm_range_fault is used to pin userptr vmas, it is possible
to map those vmas from debugger context.

v2: kmap to kmap_local (Maciej)

Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>
Signed-off-by: Maciej Patelczyk <maciej.patelczyk at intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/xe/xe_eudebug.c | 56 ++++++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_eudebug.c b/drivers/gpu/drm/xe/xe_eudebug.c
index aa383accc468..947331c19f43 100644
--- a/drivers/gpu/drm/xe/xe_eudebug.c
+++ b/drivers/gpu/drm/xe/xe_eudebug.c
@@ -33,6 +33,7 @@
 #include "xe_mmio.h"
 #include "xe_module.h"
 #include "xe_pm.h"
+#include "xe_res_cursor.h"
 #include "xe_rtp.h"
 #include "xe_sched_job.h"
 #include "xe_vm.h"
@@ -2852,6 +2853,58 @@ static void discovery_work_fn(struct work_struct *work)
 	xe_eudebug_put(d);
 }
 
+static int xe_eudebug_uvma_access(struct xe_userptr_vma *uvma, u64 offset,
+				  void *buf, u64 len, bool write)
+{
+	struct xe_vm *vm = xe_vma_vm(&uvma->vma);
+	struct xe_userptr *up = &uvma->userptr;
+	struct xe_res_cursor cur = {};
+	int cur_len, ret = 0;
+
+	/* lock notifier in non-invalidation state */
+	for (unsigned long nseq = uvma->userptr.notifier_seq; true;
+	     nseq = mmu_interval_read_begin(&uvma->userptr.notifier)) {
+		down_read(&vm->userptr.notifier_lock);
+		if (!mmu_interval_read_retry(&uvma->userptr.notifier, nseq))
+			break;
+		up_read(&vm->userptr.notifier_lock);
+	}
+
+	/* re-pin if necessary */
+	if (xe_vma_userptr_check_repin(uvma)) {
+		spin_lock(&vm->userptr.invalidated_lock);
+		list_del_init(&uvma->userptr.invalidate_link);
+		spin_unlock(&vm->userptr.invalidated_lock);
+
+		ret = xe_vma_userptr_pin_pages(uvma);
+		if (ret)
+			goto out_unlock_notifier;
+	}
+
+	if (!up->sg) {
+		ret = -EINVAL;
+		goto out_unlock_notifier;
+	}
+
+	for (xe_res_first_sg(up->sg, offset, len, &cur); cur.remaining;
+	     xe_res_next(&cur, cur_len)) {
+		void *ptr = kmap_local_page(sg_page(cur.sgl)) + cur.start;
+
+		cur_len = min(cur.size, cur.remaining);
+		if (write)
+			memcpy(ptr, buf, cur_len);
+		else
+			memcpy(buf, ptr, cur_len);
+		kunmap_local(ptr);
+		buf += cur_len;
+	}
+	ret = len;
+
+out_unlock_notifier:
+	up_read(&vm->userptr.notifier_lock);
+	return ret;
+}
+
 static int xe_eudebug_bovma_access(struct xe_bo *bo, u64 offset,
 				   void *buf, u64 len, bool write)
 {
@@ -2895,7 +2948,8 @@ static int xe_eudebug_vma_access(struct xe_vma *vma, u64 offset,
 	if (bo)
 		return xe_eudebug_bovma_access(bo, offset, buf, bytes, write);
 
-	return -EOPNOTSUPP;
+	return xe_eudebug_uvma_access(to_userptr_vma(vma), offset,
+				      buf, bytes, write);
 }
 
 static int xe_eudebug_vm_access(struct xe_vm *vm, u64 offset,
-- 
2.34.1